1. Field of the Invention
Exemplary aspects of the present invention relate to a charging device, and more particularly, to a charging device for efficiently charging an image carrier.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, and multifunction devices having at least one of copying, printing, scanning, and facsimile functions, typically form an image on a recording medium (e.g., a sheet) based on image data using an electrophotographic method.
For example, a charging device charges a surface of a photoconductor serving as an image carrier. An optical writer emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data. A development device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor. A primary transfer roller transfers the toner image formed on the photoconductor onto an intermediate transfer belt. After a secondary transfer roller transfers the toner image carried by the intermediate transfer belt onto the recording medium, the toner image is fixed on the recording medium by heat and pressure applied by a fixing device. Thus, the toner image is formed on the recording medium.
One example of related-art charging devices using a non-contact type charging method includes a charging roller. The charging roller is driven to rotate by a gear and motor assembly, and charges a photoconductor without directly contacting the photoconductor. The charging roller maintains a predetermined distance from the photoconductor, forming a charging gap therebetween.
In order to provide high-quality imaging, the charging gap needs to be kept constant with extremely great precision. However, the charging roller is susceptible to a force generated by the pressure angle of the gears which causes the charging roller to move away from the photoconductor, in turn causing uneven, insufficient charging of the photoconductor.
Accordingly, there is a need for a technology capable of preventing the charging roller from moving away from the photoconductor as described above in order to prevent such uneven, insufficient charging of the photoconductor.